I have been using a shunt fed 45G tower for many years with around 50 radials. It is top loaded with a mono stack from 80 to 10 meters. It works extremely well on 160 using an Omega match. There is a 1000 pfd vacuum variable in series with a motor driven 1000 pfd vacuum variable to ground. The motor is a reversible 1 RPM, 12 VDC motor that is tuned remotely from the shack. The SWR is always 1.3/1 or better. The tower is 100 feet high. I can usually work anything I can hear.
The receiving antennas are a Hi-Z 8, Hi-Z 2, NW BOG, and a Waller FLAG on a 40 ft boom at 93 feet. The FLAG shines on the long path. 73, John, W4NU K4JAG (1959 to 1998) Atlanta Sent from my iPhone > On Feb 28, 2021, at 10:41 AM, Grant Saviers <[email protected]> wrote: > > The nice thing about switched serial caps (if same values) for tuning > upwards from a low resonance is the voltages are all the same. Plus caps and > appropriate relays are cheap, easy, and small. > > Rick, I think you might have suggested this to me, and my implementation was > published in QEX May/June 2019. > > Grant KZ1W > >> On 2/28/2021 07:10, Richard (Rick) Karlquist wrote: >>> On 2/27/2021 2:23 PM, Artek Manuals wrote: >>> Rick et all >>> >> he feed, The taps are relay selected . Taps selected for a dip >>> at 1816, 1840 , 1860, 1880, 1900 and 1920. SWR 1.3:1 from 1.8 to 19.5 which >>> the my KPA1500 and Alpha 9500 both love. >>> >>> Dave >>> NR1DX >>> [email protected] >>> >> Thanks for posting this suggestion. Perfectly reasonable design. >> I use an alternative design using switched mica capacitors. >> I also use a 2.25:1 matching transformer, but the "windings" >> are implemented using coax. Not sure if Sevick does this. >> 73 >> Rick N6RK >> _________________ >> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
